There are known endoscopic surgical procedures carried out on the heart, involving examination and various treatments to be performed by inserting an endoscope near the ensiform cartilage into the pericardium. An advantage of such procedures is that the burden on patients is extremely low because the operation is less invasive and leaves only a small surgical wound compared with conventional medical treatment for cardiac diseases conducted surgically by opening the chest.
To achieve minimum invasiveness in an endoscopic surgical procedure that approaches the pericardium, it is desirable to make an extremely small incision through which a device is inserted. Specifically, a sheath is inserted into a small incision, and then an endoscope or treatment device is inserted into the pericardium through the sheath for examination and various treatments.
In such a surgical procedure, various types of endoscopes or treatment devices are inserted into the pericardium. For example, endoscopes include side-viewing endoscopes and forward-viewing endoscopes, which have different optical systems; flexible scopes and rigid scopes, which have insertion portions with different hardnesses and shapes; and ultrasonic endoscopes, which have optical examination as well as ultrasonic diagnosis functions. These are used in accordance with the situation during surgery and, in some cases, the inserted endoscope is switched frequently.
Meanwhile, the processor that drives the endoscope is often not suited for driving different types of endoscopes. One reason for this is that, for example, a large processor would be required. In such a case, processors used exclusively with individual endoscopes are required, and, thus, there is a need to provide dedicated image display devices for the individual processors. For instance, in a case where an image display device supporting different video formats is used, the connection between the processor and the image display device has to be switched every time the inserted endoscope is switched.
Thus, in the case where a plurality of endoscopes are used, a video-signal switching device for an endoscope system that first collects the video signals output from individual processors and then selects and switches the video signal to be input to an image display device has been proposed (for example, refer to PTL 1).